Method of coating metal molds



Patented Aug. 26, 1924.

UNITED STATES PATENT OFFICE.

DANIEL H. MELOCHE, OF DETROIT, MICHIGAN, ASSIGNOR TO EARL HOLLEY, OF

I DETROIT, MICHIGAN.

METHOD OF COATING METAL IvLGLD-S.

No Drawing.

To all whom it may concern:

Be it known that I, DANIEL H. MELOOHE, a citizen of the United States, residing at 2241 Gladstone Ave.,,Detroit, in the county of Wayne and State of Michi an, have invented certain new and use ul Improvements in Methods of Coating Metal Molds,

, of which the following is a specification.

' This invention relates to an improved method of coating metal molds; specifically it refers to an improved method of applying a protective lining to cast iron mo ds, the limng being ada ted to withstand the erosive action of mo ten metal.

One of the difiiculties experienced when it has been heretofore attempted to coat metal molds with a coating sufliciently substantial to withstand the flow of iron was that such av coating would blister and flake ofi during and after the casting operation. It is the object of this invention to apply a permanent coating which will stand repeated use and be substantially intact after a days run during which hundreds of castings are cast in the permanent mold.

The method I have discovered consists in first mixing a 10% solution of sodium silicate in water with an equal weight of finely round fire clay. Then thoroughly mixing the dilute solution of sodium silicate with the powdered fire clay, then heating the cast iron molds which may preferably be made hollow as shown in the co-pending application of Peter W. Mulder, Serial No. 541,288,

filed March 6, 1922, to from 3.00v to 500 F., then applying with a brush the mixture of fire clay and sodium silicate solution. This coating is only a few'thousands ofan inch in thickness. An air spray may be substi- 40 tuted for the brush.

Immediately after the thin coating of fire clay and soluble silicate coating is applied a Application filed March 14, 1923. Serial- No. 625,141.

flame of a blow torch is directed a ainst the surface of the freshly painted mol so as to fix or bake the coat and also to raise the temperature of the mold to what it was before it was cooled by the application of the dllute sodium silicate solutlon.

Another coating of fire clay is applied as before and the heating operation is repeated until the lining is of the desired thickness.

The mold coating of fire clay with sodium sllicate binder is described in my co-pending application, Serial No. 581,239, filed August 11, 1922. i

What I claim is:

1. The method of applying a protective coating to metal molds which consists in first heating the molds to between 300 and 500 F., then painting the heated surface of the molds with a wash containing a little soluble silicate in solution and a considerable uantity of powdered fire clay in sus ension,

t en heating the surface of the mold, then applylng another coat of fire clay with a soluble sllicate binder, again heating the sur face of the mold and repeatingthe operation until the desired thickness of fire clay is applied to the surface of the mold.

2. The method of applying a protective 7 coating to metal molds which consists of first mixing a refractory insulating powder with water containing a little heat-resisting binder in solution, then heating the surface of the metal molds to between 300 and 500 7 F then painting the surface of the heated metal mold with the said refractory wash, then heating the mold again, then applying another coating of the refractory wash, again heating the mold and repeating until a lining of suflicient thickness is obtained.

In testimony whereof I aflix my signature.

DANIEL H. MELOCHE. 

